In 23 patients with teratoblastomas of the testes the authors studied nonspecific reactivity of T-lymphocytes by means of the reaction of spontaneous rosette-formation. A definite correlation was shown between the reaction indices, chorionic gonadotropin, the Abelev reaction and clinical course of the disease. It is concluded that the complex therapy should be conducted under the control of the corresponding immunological indices.

Toxic cumulative and antitumor properties of bifunctional N-nitroso-alkylureas as compared with their monofunctional analogues were stuied. Newly produced compounds render a considerable antitumor effect on a number of experimental tumors. A conclusion may be drawn that despite changes in the chemical structure an active metabolic fragment both of mono- and bifunctional compounds is the same, as also evidenced by the cumulation index. However, inspite of a rather high antitumor activity of bifunctional compounds their chemotherapeutic indices are very low.

Special media have been developed during the past years, which provided detection of new antibiotics with the properties of antimetabolites produced by microorganisms. Antimetabolites of amino acids, vitamins and nucleic acids were found among the antimetabolite antibiotics. The antimetabolites of nucleic acids with an antitumor activity were most interesting. This group of the compounds included 5-asacytidin and antibiotic 1719 identical to azotomycin.

General toxic and myeloinhibitory effects of some antitumor antibiotics, such as rubomycin, olivomycin, bruneomycin and karminomycin administered intraperitoneally in a single LD50 to mice were studied. It was found that the general toxicity of bruneomycin and karminomycin was almost the same and 5 to 8 times higher than that of rubomycin and olivomycin. The use of the above antibiotics resulted in definite shifts in the blood systems of healthy mice. The most significant suppression of hemopoesis accompanied by a pronounced depression of the number of the myelocariocytes was observed after the use of olivomycin. The effect of karminomycin was characterized by suppression of erythro-, myelo- and lymphopoesis and depression of the number of the granulocytes and lymphocytes of the blood. Bruneomycin and rubomycin had a short-time myeloinhibitory effect. The erythroid cords of the bone marrow proved to be most sensitive to the inhibitory effect of the antibiotics. However, inhibition of the erythropoesis accompanied by deep reticulocytopenia did not induce the respective depression of the erythrocyte number. The lymphoid cords was in the 2nd place by its sensitivity to the antibiotics and the myeloid and megocariocytal cords were in the 3rd and the 4th places respectively. Complete reduction of hemopoesis in the animals was observed by the 10th day of the drugs use.

In tests conducted on mice and rats with transplantable tumours the antineoplastic activity of the racemic agent D, L-1,4-dibromo-1, 4-didesoxy-2, 3-butandiol is shown. With chronic administration of the drug in subtherapeutic and therapeutic doses a higher leucocytes count was in evidence in the blood of the animals with and without tumours.

A system for screening fungal metabolites with cytotoxic activity against tumor cells is described and the results obtained using this system are discussed. It was found that 35.2 per cent of the strains isolated from uranium mines had a cytotoxic effect on the EAC cells in vitro. As for the strains isolated from other sources only 6.85 and 9.87 per cent of them inhibited the EAC cells in vitro. Five substances, i. e. vermiculline, PSX-I, Frequentine, bikaverin and duclauxin isolated from 227 evaluated cultures showed a strong inhibitory effect on the EAC cells and other tumors in vitro.

Combined use of rubomycin and olivomycin with diacarb in treatment of rats with Pliss lymphosarcoma increased the antiblastomic activity of the antibiotics. The antitumor effect of rubomycin and olivomycin was increased by diacarb in the same degree as that of dipin, a synthetic cytostatic.

The leucocyte counts in the peripheral blood and titers of the serum lysozyme under conditions of various experimental models were compared. Albino rats, mice, guinea pigs and rabbits exposed to the effect of various factors of a biological and chemical nature were used in the experiments. In addition, observations on humans immunized with bacterial and viral vaccines were analyzed. Development of 3 reaction types was shown to be possible. In the 1st type the dynamics of the lysosome activity and blood leucocyte counts changed in the same way (immunization with smallpox vaccine, listeria infection). Decreased counts of the leucocytes due to the use of cytostatic drugs were accompanied by a parallel decrease in the lysozyme activity. Such variant of the reaction was predominating. The 2nd type of the shifts characterized by an impaired synchronous pattern of the dynamics of the indices was not so frequent (the use of high doses of cytostatics). The 3rd type of the reactions with an exactly opposite character of the shifts in the leucocyte counts and lysozyme activity was observed only as an exclusion. It is concluded that the quantitative dynamics of the leucocytes is not enough by itself for creating an opinion on the nature of the changes in the serum lysozyme. The possible role of macrophages in the above processes is discussed.

It was shown that dipin and bruneomycin resistant tumor cells appeared in mice with transplanted lymphadenosis after 10 passages on single use of the drugs. When the drugs were used in combination, no lymphadenosis cells resistant either to bruneomycin, or to dipin and their combination were found. The combined use of the drugs prevented development of resistance to them in the lymphadenosis cells at least during 10 passages on mice. The data on the possible prevention of the resistance development in the mouse lymphadenosis cells by means of combined use of low doses of dipin and bruneomycin provided an assumption that it is expedient to test the combination in clinics.

With the aid of 3-H-uridine radioautography, the effect of gonadotropic hormone choriogonin on the synthesis of RNA in the giant granular loop of XII chromosome of the Triturus cr. cristatus oocytes was studied in normal and after pretreatment of the cells with mutagen. Choriogonin, while obviously stimulating the RNA synthesis, has no effect on the cells pretreated with mutagen.

Experiments with dogs showed that daily intravenous administrations of sibiromycin in doses of 1.5 or 1 gamma/kg resulted in significant changes in the ECG: delayed heart rythm, narrowed R peak amplitude, lower P peak or its absence, presence of coronary T peak and location of S-T segment above the isoline, which corresponded to the increase in the transminase activity of the blood serum. When sibiromycin was used in a dose of 0.75 gamma/kg 30 times a day and in a dose of 1.5 gamma/kg 2 times a weak for 13 times T, P R peaks on the ECG changed. The cardiotoxic effect of sibiromycin depended on the dose. When used in a single dose of 5 gamma/kg, in a dose of 0.37 gamma/kg 30 times a day or in a dose of 2 or 1.5 gamma/kg once a weak for 7 times, sibiromycin had no toxic effect on the heart.

To reveal the cytotoxic activity of antitumor drugs the experiments were conducted in vitro-in vivo. Active substances in the dosage of 800 mg per 1 Kg of tumor were found to suppress sarcoma 45 transplantability during 1 hour in vitro. But inactive substances did it only in much larger doses. The result of the in vivo-in vitro experiments coincided with the results obtained by other investigators studying the antitumor activity in vivo. The experiments using the proposed method of selection required a much less amount of the substance (a biological experiment, repeated twice, can be carried out having 1--3 mg), animals, time and efforts of the researcher.